I can confim davemf findings, my screen looks quite similar like on the screenshot, one monitor say, 'input not supported = acer 24", Fujitsu Siemnes shows similar paterns we see" when I would like try differents settings than 1080p, 720p, 576p, 480p like 800x600, 1024*768 etc

resolutions what you see is 576p, the any of the 720p, 480p, 1080p works, none of the others (what aren't xxxp ) not working. What I can try is get a settings on second monitors (see strange pattern), when I'm probably can run the info about resolutions directly from monitors, maybe will give me a feedback about what is really set

update: today I'm not able anymore used second monitor, looks that anytime when I'm connected them, is change res to 1080p, what is too high for them, so I cannot repoduced. I'm try Sony TV and that TV showes always correct resolutions, what was selected, but screen was never good. When I'm see screen it's getting on my mind something what happend to me on kind of ARM device like last year..

I have right resolutions, but framebuffer is writing instead 32bits only 24bits. What causing very similar pictures. So pictures needs to be adjust acordingly to support RGBA instead RGB mode.. Can be somehow that, for res. like 1024x768 incorrect depth of framebuffer is used?